1. Field of the Invention
This invention is intended to serve as an apparatus that utilizes a method of processing fish heads and separating them into their various parts, thus making possible the effective use of fish heads, which generally are treated as fish-processing waste.
2. Description of the Prior Art
In recent years, the aquaculture of fish, especially salmonids, has been increasing greatly, and it is said that more than 200,000tons of chum salmon are produced in Japan each year. However, the consumption of so-called salted salmon with the head intact is decreasing in Japan, as the eating habits in this country change. In contrast, the production of flaked food, dried dainty salmon without the head, and thickly sliced fish fillet is increasing remarkably. In producing these foods, the fish head is cut off by a machine and almost all of the heads are disposed of as fish-processing waste. The disposal of such waste is becoming a social problem, and it is anticipated that the volume of such so-called waste will increase in the future.
However, the cartilage that is in the head of fish in the Chondrichthyes class, such as sharks, is well-known for being sold as a health food after it is processed into a fine powder. But it is becoming difficult to acquire the cartilage of sharks, because this shark resource itself is rare, in addition to being extremely expensive. Also, special international regulations and other factors pose additional problems. Therefore, at present, there is much interest in effectively using the nose cartilage of fish of the Osteichthyes class, such as salmonids, as a substitute for shark cartilage, which is expensive and difficult to obtain.
However, the head of a salmonid is very unsanitary, with blood around the gills, secretions in the epidermis, and so on. Moreover, it is easy for a worker to have an accident while using a knife, such as a kitchen knife, to remove the nose cartilage from the head. In particular, because the epidermis is slippery, workers can easily lose their grip on the fish head and cut their hands. Thus, this work is time consuming and requires that workers pay close attention to what they are doing. As a result, productivity is low and very costly. As a result, vigorous efforts are not being made to use the above-mentioned salmonid head effectively, and there has been little study concerning the possible nutritional value or other beneficial uses of the constituents of the nose cartilage of such a fish. Thus, the possible applications for using such nose cartilage in or with various kinds of foods are not being realized.
Nose cartilage accounts for approximately 10.0% of the weight of the head of a fish such as a salmon. Moreover, proteoglycan, which is a conjugated protein, exists in nose cartilage. Chondroitin sulfate is an acid mucopolysaccharide that removes a particular protein from proteoglycan. Related to this, a recent study showed the following: Chondroitin sulfate accounts for approximately 3.0% of the weight of the nose cartilage and for approximately 0.3% of the weight of the entire head. In laboratory experiments, chondroitin sulfate has been extracted from the head of salmonids, particularly from the nose cartilage, and various studies relating to the medical effects of such chondroitin sulfate have begun. However, if the cost of producing nose cartilage, which is the necessary raw material from which chondroitin sulfate is extracted, is considered, the cost of producing chondroitin sulfate is very high. Productivity is low because there is not available a system that improves the cost performance relating to the use of fish heads. As a result, the manufacture of chondroitin sulfate from the heads of salmon is limited to the small-scale level of refinement that is possible in a laboratory.
Chondroitin sulfate accounts for approximately 0.3% of the weight of the entire salmon head. However, although the head itself is waste and the purchasing cost pr sales value thereof is zero, the cost of extracting chondroitin sulfate for business purposes is very high. If all of the direct and indirect costsxe2x80x94such as the transportation cost sand deep-freezing storage fees for the head; personnel expenses; lighting and heating costs; machine and equipment expenses; and so onxe2x80x94involved in extracting chondroitin sulfate, which constitutes only 0.3% of the weight of the head, are totaled, to extract such chondroitin sulfate is too expensive to be conducted as a business. The high costs are a big fetter that in effect prohibit the production of chondroitin sulfate.
Because the cost of producing only chondroitin sulfate is too high, it is not feasible as a business activity. The solution to this problem, therefore, is to develop a processing method that offers high cost performance by using, in addition to the nose cartilage, the other parts of the fish head; i.e., the residues that account for 90% of the weight of the head. In addition, an improvement (i.e., increase) in the percentage of chondroitin sulfate (which has a high value) that is extracted from the raw materials, also is necessary.
The objective of the subject invention is to solve the above-mentioned problems by serving as an apparatus that easily and accurately: (1) processes fish heads so as to separate them into their various parts, and especially to separate the nose cartilage from the rest of the fish head, (2) separates the end proboscis part and the other rear parts from the nose cartilage, (3) processes the above various parts of the fish head, including the residues, into forms that can be used in manufacturing products of commercial value.
The subject invention""s method of processing a fish head has the following characteristic step: to break apart a fish head and to separate the nose cartilage from various residues by rotating the fish head and giving an impulsive force to it after it has been heated and softened.
In more detail, a fish head is heated and softened and then the hot fish head is put into a rotary drum of which the surface is a round net-like body. A plurality of plate blades are affixed either to the inside of the rotary drum or to the shaft of the drum, opposing each other in the direction of the drum""s circumference and axial plane, respectively. By rotation of the rotary drum, the fish head is rotated and crushed against the plate blades and then the fish head is separated into the nose cartilage and various residues.
In the second step of the process of separating the aforesaid nose cartilage into the end proboscis part and the rear part, the nose cartilage is put into the aforesaid rotary drum of which the surface is a round net-like body. A plurality of plate blades are affixed either to the inside of the rotary drum or to the shaft of the drum, opposing each other in the direction of the drum""s circumference and axial plane, respectively.
Moreover, the method of this invention comprises the following steps: making paste by removing fats after making comminutions of the above-mentioned nose cartilage that has been separated by the aforesaid process, making a meal by grinding the aforesaid residues; making a paste by removing fats after making comminutions of the aforesaid end proboscis part; making a paste of the aforesaid rear part; making a raw material from which to extract chondroitin sulfate after removing the fats of aforesaid nose cartilage; making a powder from the paste of the aforesaid end proboscis part; and making a powder from the paste of the aforesaid rear part.
This invention""s apparatus for separating the processed parts of a fish head of that is used in the aforesaid methods of processing comprises: a shaft that rotates by being driven by a rotating means; a plurality of support members that are separately joined to the shaft in the axial direction of the shaft; a rotary drum made of a net-like body that is rounded at the aforesaid support members, that forms a processing space into which is put hot said fish head (in particular, the net-like body of the rotary drum being formed by a plurality of reticles that are of various sizes according to the desired type of processing of the aforesaid fish head), and that is freely movable from said support members and is exchangeable; and a plurality of plate blades that are installed in the rotary drum and that project into the aforesaid processing space.